SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31ac690fb18226d62449bd38a5d766ec25b2513c662b4eef22deceaf517a59b6' 
  AND token = 'EjbRC4GwNpk+agyvRjSFDCxv5A+DSykwt0fJJdNm9P4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}